P0118 Fault Code

Engine Coolant Temperature Circuit High Input

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0118 fault code indicates that the Engine Coolant Temperature (ECT) sensor is reporting a high voltage signal to the Engine Control Unit (ECU). This typically means that the ECU is detecting a coolant temperature that exceeds the normal operating range, potentially leading to overheating or incorrect engine performance. Commonly, this code is triggered by a faulty ECT sensor, damaged wiring, or issues within the ECU itself.

What are the symptoms of the P0118 code?

Drivers may experience various symptoms associated with the P0118 code, such as:

• Check Engine Light illuminating on the dashboard
• Poor fuel economy
• Engine overheating
• Erratic engine performance or stalling while driving
• Increased emissions due to incomplete combustion

What causes the P0118 code?

There are several potential causes of the P0118 fault code, including:

• A malfunctioning Engine Coolant Temperature sensor
• Short circuit or open circuit in the wiring harness leading to the ECT sensor
• Corrosion or damage in electrical connectors
• Issues within the Engine Control Unit (ECU)
• Engine overheating due to a cooling system failure

How to fix P0118?

To resolve the P0118 fault code, you can follow these steps:

• Inspect the Engine Coolant Temperature sensor and its wiring for damage, corrosion, or loose connections.
• Replace the ECT sensor if it is found to be faulty.
• Check the ECU for any software updates or issues.
• Ensure that the coolant system is functioning properly and that there are no leaks leading to overheating.
• Clear the fault codes and test drive the vehicle to ensure that the problem is resolved and the Check Engine Light remains off.